radars are of two types pulsed and continuous wave radar.

pulsed radar has its carrier pulse modulated used for detecting stationary objects

continuous radar uses direct sine wave for transmitting and is used for moving targets

there are types such as weather, and aircraft.

frequency modulated continues radar for detecting the target it generates the signals by continuously.

Radar Pulse Repetition Frequency - The number of pulses the radar system sends out to the target. A pulse can contain multiple frequencies.

CW or continuous-wave radar cannot determine range due to the lack of a listening period where the radar signal is silent. Pulse radar has a silent listening period (hence the name pulse radar). Therefore it can determine the range of the object causing the return by counting the elapsed time between transmission and receipt of the echo. The above is not quite correct, Continuous Wave Radar and Pulsed Radar differ by there relationship between the Pulse Width (tau) and the scene size (Swath). CW Radar's determine range by Frequency Modulation (FM) ranging this means that they ramp the RF frequency within the pulse during the transmission and are known as FMCW Radar. Pulsed Radar on the other hand use the pulse timing but can also use the FM Ranging trick to enhanced there signal to noise and reduce there probability of interference or detection/interception. CW radar can deduce range by delaying the transmit signal and mixing it with the receive such that it becomes a homodyne receiver and in such cases it is usual to ramp the RF and perhaps use two aerials rather then just one with a duplexer switch like in a Pulse radar system.

Edit- hmm i feel the above answer is bit too complex... i don't think typical person would go as far as concerning FM or Pulse Delay Ranging

here's my Answer

DIFFERENCES BETWEEN PULSE AND CW RADAR

Basis -Transmission Pulse RADAR puts delay between transmitting and receiving periods so the time between transmitted pulse and received pulse is different

While CW RADAR, Transmit continuously

-Antennas Pulse RADAR may use same antenna for Receiving and Transmitting , when transmitting the receiver is "blanked" and while Receiving the receiver is Activated and transmitter is blanked .. this is done by a device called "Duplexer"

CW RADAR typically used 2 Antennas, one for transmit another one to Receive since there are no delay to receive as what usually seen in pulse RADAR

-Ranging technique

Pulse RADAR may use "Pulse Delay Ranging" to provide Range measurements , Frequency Modulation Ranging may also possible , especially for pulse RADAR that transmit many pulses and have very shot time to "listen"

example is FMICW (Frequency Modulated Interrupted Continuous Wave RADAR)

While CW RADAR provides Range by means of Doppler based Ranging (FM Ranging)

CW Radar or Continues Wave Radar uses a constant transmission and is usually used for angle only tracking and can be combined with a second emission that is pulses or swept to deuce range using and separate antenna (or on a time schedule in some cases). The CW part of a CW Radar reference to the transition duty Ratio and because Dead and Listen time are over lapped they normally have two antennas. FM CW Radar or Frequency Modulated Continues Wave Radar, is similar to the CW set up but the Carrier Radio Frequency is swept, when processed this data can produce range data. Again the Dead and Listen time our overlapped and it is normal for separated antenna to be used. The Frequency sweep is repeated in successive management ion different angles Pulsed Radar Transmits a short pulse rather then continuously like the FMCW Radar or CW Radar and has a short Dead time and long listen time During the dead time when the transmission pulse is emitted the receiver is blanked to protect it, After the pulse has completed transmission the receiver is opened to receive the returns. This means that the receiver and transmission times are mutually exclusive and therefore the same antenna can used for both jobs. As the pulse is short the transmission peak power maybe higher then the CW Power but is present for less time. I Hybrid Radar is ICW or Interrupted Continues Wave (some times called Interrupted Carrier Wave) which is really a pulse radar with a high duty cycle.